Text Factorise as a difference of squares: (a) x2−9x^{2}-9x2−9 (b) 4x2−494x^{2}-494x2−49 (c) 25x2−125x^{2}-125x2−1 Solution (a) x2−9=(x−3)(x+3)x^{2}-9=(x-3)(x+3)x2−9=(x−3)(x+3). (b) 4x2−49=(2x−7)(2x+7)4x^{2}-49=(2x-7)(2x+7)4x2−49=(2x−7)(2x+7). (c) 25x2−1=(5x−1)(5x+1)25x^{2}-1=(5x-1)(5x+1)25x2−1=(5x−1)(5x+1). (a) (x−3)(x+3)(b) (2x−7)(2x+7)(c) (5x−1)(5x+1) \boxed{\;(a)\;(x-3)(x+3)\qquad (b)\;(2x-7)(2x+7)\qquad (c)\;(5x-1)(5x+1)\;}(a)(x−3)(x+3)(b)(2x−7)(2x+7)(c)(5x−1)(5x+1)